they are mostly used in environments for the environment, whether it be the sand in the desert or the jungle, it would interfere with the explosive. that has been traditionally their use. that being said, these things are easy to find, easy to make. i don't have to tell you, you can look up on the internet and see the step by step instructions on to do that. and matter of assembling the various ingredients you would do to put it together. that to expand on what he was saying, they are getting a lot of evidence how the bomb was made but they don't have a lot of evidence about who did this or why. the actual evidence that would lead to the person or persons involved. >> this suggests a slightly higher level of them what was first thought yesterday and if so, does that narrow down the net of potential suspects? >> it does. the black powder, the acetone, peroxide, you don't want to let it get went. absolutely right. you want to protect the explosives, the detonator. when this bomb went off, talked to a couple of people and their first reaction was what is happening to people coming back f